The goals of this proposal are (1) to perfect an isolated hypothalamus model using fetal rat hypothalamus transplanted to the anterior chamber of the eyes of adult female rats, (2) to study the maturation of structure and function in such transplants to document their ultra-structure and immuno-cytochemistry in terms of GnRH and catecholamines, (3) to examine the release of GnRH and catecholamines by the hypothalamic implants into the aqueous humor of the eye and into the local and systemic circulation, (4) to examine the effect of local, systemic and micro gonadal steroids, catecholamine and electrical stimulation on the production of GnRH by the implant, (5) to examine the developing vascular, neuroultrastructural and physiological relationship between additional transplants of anterior and posterior pituitary, hippocampus, amygdala and pineal gland placed adjacent to the hypothalamic implants. The experimental techniques will make use of microsurgery, light and electron microscopy, immunocytochemistry and radioimmunoassay. The final aims of this study are to throw further light on the intrinsic workings of the hypothalamus in a system in which is separated from the anterior pituitary gland and the rest of the brain. The effect of gonadal steroids and catecholamines will be studied in this situation and such work will provide furter information that will be useful to the elucidation of reproductive endocrinology problems in the human (contraception, dysfunctional uterine bleeding, pituitary tumors, amenorrhea, polycystic ovarian disease and post-menopausal syndromes).